1. Field of the Invention
The present invention relates in general to a weather strip for automobiles, and more particularly, to a material of the weather strip, which eliminates or at least minimizes the uncomfortable squeak produced when the weather strip rubs against a glass pane, such as a door glass or the like.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional weather strip used in an automobile will be outlined with reference to FIGS. 2 and 3 of the accompanying drawings.
In the drawings, particularly FIG. 3, there is partially shown a motor vehicle of the so-called "pillerless hardtop sedan type", to which the conventional weather strip is applied. Denoted by numeral 1 is the weather strip which is interposed between a front door glass 2 and a rear door glass 3. As is seen from FIG. 2, the weather strip 1 comprises a gripping portion 1a having a generally U-shaped cross section, a supporting wall portion 1b extending obliquely inward from an inboard side of the gripping portion 1a and a lip portion 1c extending outward from the leading end of the supporting wall portion 1b . The gripping portion 1a grips a front edge of the rear door glass 3. The lip portion 1c is contactable with the front door glass 2 to achieve a watertight sealing therebetween.
Hitherto, as the material of such weather strip 1, ethylene-propylene-diene-methylene (EPDM) has been widely used for its tolerable antiweatherability and reduced cost.
However, the weather strip made of such EPDM, particularly when used, for long periods tends to produce an uncomfortable squeak when the door glass 2 rubs against the weather strip 1, more particularly, against the lip portion 1c of the same or vice versa.
In order to solve this drawback, several measures have been hitherto proposed and put into practical use. One of the measures is to apply the weather strip with a surface treating agent to reduce the skin friction of the weather strip. Furthermore, Japanese Patent First Provisional Publication No. 61-238507 shows a measure of using acrylonitrile-butadiene rubber (NBR)/polyvinylchloride (PVC) as the material of the weather strip for reducing the friction.
However in the former measure, the durability of the surface treating agent is inevitably poor because the agent tends to peel off due to repeated opening and closing movement of the door glass 2. Furthermore, the latter measure has failed to produce a satisfied result in minimizing the squeak.